0.68 oz with battery, and about 15 hrs of light on the 20L setting per AAA energizer ultimate Lithium battery.

Now, 20L isnt a lot, but I have about 10+ hrs hiking time in the dark with it on the AT, and its enough for me. I like to start hiking an hour or two before daylight. This light really rocks battery life on that setting with the energizer lithium. Will get maybe 1.5 hr on the high 70-80L setting.

I use one light for flashlight, headlamp, and lantern. You will get a lot of Olight recommendations in this thread, as above. I greatly prefer 186500 battery cells, they have a great weight/power ratio and extreme durability (they are the cells used in laptop batteries). Olight's offerings with an 18650 cell are 3x the price and 3x the weight of the one I use.

The flashlight: ShiningBeam S-Mini with Cree XP-G-R5 emitter (45g)http://www.shiningbeam.com/servlet/the-152/ShiningBeam-S-dsh-mini-XP-dsh-G-R5/Detail
The light has 3 levels of brightness and NO annoying blinky modes: Low 9.5 lm (24mA), Medium 155 lm(400mA), High 360 lm (1,000mA). With my 3100 mAh 18650 cell I get over 3 hours continuous on high, 7:45 on medium, and 129 hours on low. This is with a constant current circuit; the light doesn't dim as the battery weakens.

If you go to the CPF forums, you can read a tremendous amount about headlamps in the dedicated subforum–which, by the way, is filled with hikers, cavers, and bicyclers. If I were to guess at the most commonly recommended headlamp for backpacking by the CPF'ers, it would be the ZebraLight H52F, because that beam is a center-weighted flood, so does duty both for night hiking and for trail chores. It's small, efficient, and hardy. If it were me, I'd avoid the cool white version.

The light is so efficient, there's no need to turn it off at night. Just turn to one of the sublumen modes, and set it in the corner of your tent, or clip it to a guy line, so you can easily find it when you need it. The light will run continuously for 2-3 months in the lower sublumen modes from a single AA battery.

Weight of the light is 32 grams / 1 oz. On high (depending on model) it can blind you with as much as 300 lumens.

You can get it in "flood" (H52F) or regular (H52) which is still fairly floody and a good choice. And you can get it in "cool white" (brightest) or "neutral white". So all told there is the H52, H52F, H52w and H52Fw.

Thanks for that link! I wasn't aware of that charger/power pack and at that price (and weight) it's an incredible find. I've have the Zebralight H600 Mk II 18650 XM-L2 Headlamp and use 3400 mAh (18650) batteries. Although it's heavier than my H52W AA headlamp, the long run time and of the H600 means I don't have to carry extra batteries so for longer trips, it's probably a lighter (more versatile) solution. The fact that I can alos carry the charger mentioned at the link provided above, means I can do double duty with these high output batteries.

The beauty of the H600 is that you can set it for the output you require for backpacking and get incredibly long runtimes. My favorite levels are 160 Lm (11 hrs)
and 70 Lm (30 hrs). The 70 Lm setting is a very good level for night hiking and it will run at that level for 30 hours which is incredible! The fact that the H600 can also put out over 1000 lm for up to 2 hours makes it stupid bright (you don't need that much light) but it's impressive.

H52w AA Headlamp is a really good light as well and because it takes AA lithium cells it's my favourite for backpacking but the power supply device mentioned above is going to make me rethink whether the H600 may be a better all-round solution. The H600 is my choice for fishing trips (day trips) where I often walk out in the dark.

The H52W AA headlight weighs in at 2.5 oz with an AA lithium cell
The H600 headlight weighs in at 4.0 oz with a 3400 mAh 18650 battery (centre head band strap removed).

Since I'd have to carry a couple of extra lithium cells to match the extended battery life that the 18650 batteries provide, I think the weight pretty much balances out on longer trips.

One of the interesting things I discovered about the H600 is that the head band strap is so stretchy that I can actually wear the light around my waist just by extending the strap to full length. I have to "step into it" to wear it this way but I might add a release clip onto the strap so that I can just wrap it around my waist.

I wanted single battery lighting and use a Fenix. HL21 and an Olight i2 flashlight, both using a single AA. I can carry one spare that will fit either and also have the option of switching between the two if necessary. It is far easier to replace a single battery in the dark than fumble with three AAA's. The AA lights are a bit heavier but seemed to have more bang for the buck than the single AAA models.

I'm glad you can get use out of that battery cradle. One important thing to consider – the one linked will NOT accept most protected cells without modification of the negative "-" side bar spring. There is an older version floating around, perhaps an international eBay seller will have it. That older model has a coil spring negative terminal that works with most protected cells. My light has auto shutoff and I bet your Zebra light does as well. You can still find good Panasonic and Sanyo cells without protection, but I typically just remove the shrinkwrap and yank the protection circuit off my cells.

In my previous post I forgot to mention the popularity of Zebralights as evident by 3 mentions in a short while; VERY popular brand. Fenix will show up here sooner or later, as Delmar mentioned there is likely CPF overlap here.((edit:Fenix appeared as I was typing.)) Zebralight seems to stay on the bleeding edge of getting the most output for the least input in their entire line. The interfaces are a bit convoluted to me but I'd deal with something like that for their performance IF it wasn't a $90 light. I just can't stomach the cost.

Perhaps at some point the LED and driver technology advances will slow, and the lumen race will end. The performance of XPE-Q and XRE-Q LEDs that were prominent 5 years ago were getting 200 lumens with much shorter run times. Today's XM-L and XP-G LEDs are providing 300+ lumens when driven lightly allowing for longer runtimes and reduced heat. The reduced heat has the added benefit of lower weight since less heat sinking is required. The state of the art light from 5 years ago can't match the performance of a $10 light today. Certainly the Zebralight will stand up to negligence/abuse longer than a cheapie, but $10 gets you a durable triple O-Ring Sealed 18650 light with an XPG-R5 LED that provides 300lm OTE.

I bought the $30 S-Mini in 2012 and will probably look to upgrade to another $30ish light in another year. $10/season seems like a good number to me.

I have a couple of Petzl XP2 headlamps with the Core battery. Not the lightest, tiniest, whatever, but it has useful light levels, flip up diffuser, charges off USB, etc. Works for me – use them all the time.

+1 on not overthinking it. Flashlights are cool toys to geek out on, but unless you're caving, winter camping, or planning your hike around nocturnal activities, anything will do. People have lived for thousands of years without artificial lighting.

All of the lights here are excellent choices IMO, some even have me wanting to add to my collection again :)

The question really lacked any defining parameters, usage, battery preferences, etc., so I guess I'd suggest just walking into an REI and playing with all the display models. Find one that YOU like.

I have been quite happy with my zebralight. I have had the predecessor to the h52, the h51w since it came out. That was about 3 years ago. This light does almost everything for me and rides in my pocket every day on the pocket clip. Several times it has gone through the wash, many times been dropped onto hard surfaces, and it keeps going.

The clips allows for handsfree usage without the headband if needed for weight purposes. It goes well clipped between buttons on a buttonup shirt, or clipped to the side of a baseball hat.

The only time I have found myself wanting more light is for bicycle commuting after dark on the street, where you need a similar intensity of light as the cars to be able to see well.

I very much disagree with the "don't think too much about a headlamp" advice.

First, we think about EVERYTHING here on CPF. Heck I posed a question on rubber bands and got lots of thoughtful answers. Why not about an expensive bit of electronic gear, upon which your life might someday depend? People will tolerate excruciating detail about windshirts and plastic groundcloths…what's wrong with detailed information about flashlights?

Second, when I started taking the quality of my flashlights seriously, I started seeing much better, in many more conditions. Seeing is actually important. The quality and volume and dependability of light is important. Most of the functioning of the human brain is devoted to processing visual stimuli. Why the heck would I "not think" about feeding my eyes?

Third, headlamps vary significantly in terms of their reliability. You need to inform yourself, before you know which brands are known for giving out, and which are renowned for carrying on. Even the best headlamps have known weak points that you should know about.

So my recommendation is: think about it. Thinking too much is less risky than thinking too little.

Plus, it seems like so many headlamp purchasers are chasing after something that will put a spot on a wall farther and farther away. Instead, I go after one with a flood pattern so that I can see better the stuff around me. Also, I've been known to shoot photos at night using the flood, and it looks a lot more natural than if I had been using a spot.